Dodging The Frost Bullet

Going right from high summer to early fall this year!  Just last week it was in the 90s, and now we are getting 40s – 70s for temperatures every day. Monday night we even got down to 38F here in Bakerton. Normally our first frost wouldn’t be until mid-October, though just 30-40 miles to the west, over the Allegheny Front, it would be fairly normal. This really shows the importance of micro-climates.

Those of you have heard one of my talks know that I am big on the idea that most anybody can be successful at gardening if they just follow a few basic principles, and pay close attention.

Two of the interlocking principles that I talk about involve paying more attention to the weather (and phenology) than to the calendar, and to never forget that it is the plant’s environment that matters more than your own when trying to figure out how to enhance the health and productivity of the garden.

In my lectures, I always show three pictures I took back in Pennsylvania three Marches ago: one of the thermometer on the wall (reading 40F) followed by one fastened to the garden fence so the bulb is right at soil level (reading 32F) and the third of a soil thermometer (reading 20F or so). A lot of gardeners are like the fool who looks for his lost car keys only under the street light, because “that is where the light is.”

We look at the eye level thermometer “because that is where the light is,” but the plant, of course, is at ground level, and the seed is an inch or more down in the soil. Their microclimates are very different. Here is a classic example from last spring.

It was clear night , with a near full moon setting, and while there was no frost on the grass of the front yard, I did find that the water in some of the puddles on the garden tarp had frozen over with a thin skim of ice. The amazing thing was that the two puddles, no more than a foot apart, were different — one frozen, one not.

080324_003Now what could cause that? One just slightly deeper, and thus with more thermal mass — just enough that it didn’t freeze? Or just that it was a few tenths of a inch higher or lower (due to the rough surface beneath)? Or maybe just that something in that spot of the garden was decomposing under the black plastic and creating a bit of microbial heat? It really brought home to me just how much complexity and variation there is even in the smallest space!

Note: you need to look really close to see the difference…but notice that the puddle on the right is showing a reflection of the trees — it is the unfrozen one — while the puddle on the left does not reflect due to the crystalline structure of the skim ice…

ShepherdDodging The Frost Bullet